hello brand new to forum, just bought 2 weeks ago a 2019 wrx with 27k also came with a cobb intake and cobb accessport and maybe others???

so when i bought the car i knew something was up.. the mechanic straight out told me i needed a pro tune, but then on drive out of dealership the car gave me a check engine light.... like wtf, go back to the mechanic and he gives me that cobb accessport for free which is pricey, and redo my tune? and check engine light never came back since, but it sputters at load like if i actually try to put the pedal down it can sputter, im gettin weird data feesd like ive seen -1.41. learning, ive seen numerous bad feedback knocks highest ive seen was once in 93 octane build a -4.83 or something ever since that day cobb dropped my tune down to a 91 big sf tune and its been ok u know -1.41 here and some -2.81s but nothing bad, then i also stopped using safeway 92 and went to a 76 station with more cleaner gas been ok but still higher mphs im gettin weird data hits, soo tuesday im taking this thing into a cobb gold certified tunner and im like sweating it, idk what this gonna cost hes like i gotta check everything out and blah blah im like i dont got shit for cash LMFAO soo im hoping he dont charge me alot. man i think also my exhaust is diff i hear other wrxs then u have mine which is pretty burly sounding than rest, def can hear that air suck in air for sure! everyone hears me coming.